Semi-automatic firearms have been known for a long time. The first semi-automatic rifle was introduced in 1885. The M-16 automatic rifle has been used by the military for years. A civilian version of the M-16 is known as the AR-15 and is a semi-automatic rifle. The AR-15 has been manufactured and sold to civilians for many years. Standard AR-15 semi-automatic rifles are manufactured and distributed with takedown pins. Takedown pins are utilized to secure the upper receiver to the lower receiver. To access the action, a user needs to remove the takedown pin. The user may then separate the lower receiver from the upper receiver. The user can clean the firearm or otherwise access the action. When done the user can then reattach the upper receiver to the lower receiver. The user inserts the takedown pin into the channel to secure the upper receiver to the lower receiver.
Standard takedown pins may be deficient. A detent pin within the body of the receiver may hold a takedown pin in place. However the takedown pin may still be fully removed. This presents an issue if the user misplaces or loses the takedown pin. What is needed is a takedown pin which is specially designed such that it is easy to remove and reinsert and which is not easily fully removed from the firearm.